Flood watch for Maryland

The NWS has issued a flood watch for us until late tomorrow. As I have been mentioning these past few days, our current weather pattern has us in a wet and stormy weather through most of the coming week. Each day there is the chance for strong pop up storms containing gusty wind, hail and heavy rain.

The text of the watch is below. Follow me on Twitter (@wxmanmd) for weather tidbits and updates.

-------------------------...Flash Flood Watch in effect from this evening through lateMonday night...

The National Weather Service in Sterling Virginia has issued a

* Flash Flood Watch for portions of Maryland...the District of Columbia and northern Virginia...including the following areas...in Maryland...Harford...Howard...Montgomery...norther n Baltimore...Prince Georges and southern Baltimore. The District of Columbia. In northern Virginia...Arlington/Falls Church/Alexandria and Fairfax.

* From this evening through late Monday night

* numerous showers and thunderstorms will develop by late today...with occasional showers and thunderstorms continuing through at least Monday evening. These showers and thunderstorms will contain very heavy rainfall...with an inch or more of rain possible. Since several thunderstorms may track across the same areas...at least 2 to 3 inches of rain will be likely. Due to wet conditions...this much rainfall would cause flash flooding to develop.

* If flash flooding were to develop...roads may become impassable. Expect rapid rises along creeks and streams.

Precautionary/preparedness actions...

A Flash Flood Watch means that conditions may develop that leadto flash flooding. Flash flooding is a very dangerous situation.

You should monitor later forecasts and be prepared to take actionshould flash flood warnings be issued.

Saturday storms Maryland

We can expect more of the same today as we had these past couple days. The #storms may not be as frequent nor severe today as we saw yesterday, but scattered storms will pop up in the afternoon nonetheless. Keep an eye on the #sky and your #weather radio on.

same pattern in Maryland til mid-next week

The weather pattern we have had these past days will continue through mid-next week. As I mentioned a couple days ago, the formation of the trough and various Low pressure systems moving through the area are to blame. Each day there will be scattered storms, some severe. Just as yesterday, not everyone will see a storm, but they will be in the area and could pop up quickly.

TIMING: Each afternoon every day through mid-next week.

THREATS: Heavy rain, damaging winds, and hail. Tornado threat is low.

Keep an eye on the sky each day as these storms could form quickly. The more sun in the morning the stronger the storms in the afternoon. Follow me daily on Twitter (@wxmanmd) for weather tidbits and information.

storms in Maryland today

As I mentioned yesterday, #storms, some severe, are probable later today. The warm moist air moving up from the south (thanks to the Bermuda High) is in place as a cold front moves into the area. The heavier cold air will force the lighter hot air higher into the atmosphere causing the potential for storms. The only "possible" feature keeping down the severity of any storm development is the cloud cover we have been experiencing. Typically I would have said that the cloud cover will prevent storms, but even without the heating of the sun, the dewpoints (again, thanks to the High) are high enough to cause instability.

TIMING: Storm development should happen after 2:00pm into the evening.

THREATS: Strong damaging #wind, #hail, torrential #rain are the main threats. An isolated #tornado is not out of the question.

So far no watches/warnings are issued but I expect that to change. Keep an eye on the sky and your weather radio turned on. Follow me on Twitter (@wxmanmd) for updates on the storm.

hot and wet in Maryland

Enjoying the heat? The #Bermuda High off the coast is to blame, and will stay put through the next day. A Bermuda High is called so due to it's position in the Atlantic and the subsequent hot and #humid air it pumps into the region. Recall that a High pressure system spins clockwise, and given it's current position that places us around the 7:00 position with the winds bringing up warm humid air. Warm air rises, cooling with height in the atmosphere. This is one of the reasons we have towering cloud formations #Summer afternoons. And, what goes up must come down, hence rain, hail and wind.

All this to say that today will be similar to yesterday in that as the heating of the day cranks up the potential for strong #storms later this afternoon increases. The main threat from the storms will be damaging #wind and #hail. #Tornado threat is nil.

Tomorrow a cold front enters the area, and when the cold air bumps into the warm moist air we end up with the potential for severe weather. The timing on this should be later afternoon Thursday.

Then, once the cold front moves through the Bermuda High is pushed away, good for those who don't like the heat and humidity, but the resultant set up is a strong trough ("U" shaped flow in the atmosphere) near us. This means cooler air is pulled down from Canada, and moisture is pulled up from the Gulf. Therefore, a bit cooler, but the potential for daily storms and lots of rain through early next week.

Thus far there are no watches/warnings issued but I expect that to change as the day progresses. Follow me on Twitter (@wxmanmd) for weather tidbits and storm updates.

Tuesday storms in Maryland

This nice weather will not be totally ruined, but with an approaching cold front out of PA and some Low pressure systems sliding through, Tuesday into Wednesday we will see more widespread storms than we have seen these past couple days.

TIMING: The rain for most areas should hold off until 1:00pm or later Tuesday with the bulk of the storms late afternoon into the evening. The rain and some storms could persist into Wednesday morning.

THREATS: There is a possibility of some sheer formation, and if so we could see gusty damaging winds. But, since the day should be cloudy most of the instability will not be able to form (if I'm wrong and it's sunny most of the day, then the storms could be stronger).

Fathers Day storms Maryland

Happy Fathers Day! Unfortunately, today will not be what they have been these past couple days. The temp is on the rise, and the storms are coming. The High pressure system, keeping us dry and cool, is moving off the coast while behind it is a Low and a weak cold front. As the High moves the winds shift and the southern temps move in.

Today, rain will start as scattered but become more widespread as the day progresses. Storms are possible later this afternoon, and those who experience the storms could see gusting winds and hail. The next couple days will be the same, although Tuesday's weather could be more severe. More on that later.

Thur afternoon UPDATE to Maryland severe weather

We are currently under a Flash Flood Watch and a Severe Thunderstorm Watch through this evening, although, as I mentioned last night, the clouds and morning rain took away a lot of the instability and fuel for storms. The latest SPC moved all the severe weather out of Maryland and into VA. ....

.... But, that doesnt mean there wont be storms later this afternoon. Storm formation is not just dependent on the amount of sun light and heating. As other factors are still in play we all need to be cautious. Storms may pop up suddenly, as one did in S MD late last night. Just because there is no tornado watch does not mean an isolated twister can't happen.

I must say, though, that as I have ranted here and on Twitter, the fact that no derecho formed (never thought it would) and now the severe threat is moving south of us, media outlets need to stop hyping the weather and scaring people. I tried to present a balanced forecast here and I hope it was helpful. But again, the threat for storms does exist for us today.

TIMING: Most of the storm activity should start after 3:00pm.

LOCATIONS: Central and S MD are in play, although S MD could get the brunt of the storms (as I mentioned in an earlier post).

THREATS: Damaging wind and flooding rain. Tornado threat is low but formation is still possible.

Thur morning UPDATE Maryland severe weather

The Storm Prediction Center (SPC), just an hour ago, still has Maryland in a moderate risk for severe weather this afternoon. The rain and clouds this morning may have stabilized the atmosphere a bit, thereby weakening future storms (as I mentioned last night might happen). But, the quicker the sun comes out our chances increase for severe weather. Plus, there are other factors destabilizing the atmosphere, not just the heating from the sun. Therefore, stay alert for severe weather later today. This morning was only round one. We arent done yet.

The SPC has also placed our area in a 10% risk for tornado development and a 30% hail risk. The wind risk is placed at 45% chance of wind gusts over 52 mph and a 10% chance of wind gusts over 67 mph.

The exact timing of storm formation is hard to tell, but should be after 3:00pm today. Keep your weather radio turned on and an eye on the sky.

Follow me on Twitter (@wxmanmd) for storm updates. Not on Twitter? No problem, go to www.twitter.com/wxmanmd and follow me there.

UPDATE Maryland severe weather

As I write this, after midnight, #storm cells are forming over S MD triggering a #Thunderstorm Warning for Calvert & St. Mary's counties. This storm cell is currently 49,000 feet in height which is quite the sizable storm!

Again, I will not burden you with the storm dynamics, email me if you wish to know more, but thus far the storm system in the mid-west has been powerful and is heading our way into #Maryland. As I had previously stated, our storms weren't to begin until after midnight lasting into late Thursday. Here is what the local NWS had to say: "THERE IS RISK FOR A SIGNIFICANT SEVERE WEATHER EVENT THURSDAY AFTERNOON...WITH THE POTENTIAL FOR WIDESPREAD DAMAGING WINDS AS WELL AS LARGE HAIL AND A FEW TORNADOES."

TIMING: Storms will pop up anytime now through Thursday evening with the worst of the weather after 2:00pm Thursday.

POTENTIAL BUST: There is a chance the storms will not produce as forecast, although I do believe we will see strong to severe storms. But, the mountains may break apart the current line of storms heading toward us, leaving us with scattered storms and rain, and lots of clouds. If there is a cloud deck through the morning hours that may inhibit some of the heating of the day and help to somewhat stabilize the atmosphere. If there is a good amount of sun all day, the storm potential increases.

I will have another update later Thursday morning. Keep your weather radio turned on. Follow me on Twitter (@wxmanmd) for storm updates and info.

Maryland severe outbreak

For the sake of getting out the pertinent information, I wont state all the meteorologic reasons for why the storms are forming, but if you want to know the details email me and I will get back to you. Suffice it to say, tonight into tomorrow could get rough at times. Here is a quote from the local NWS forecast discussion sent to local forecasters: "THE MID-ATLANTIC WILL SUFFICIENTLY DESTABILIZE AND BE PRIMED FOR WHAT COULD BE A SIGNIFICANT SEVERE WEATHER EVENT DURING THE AFTERNOON AND EARLY EVENING."

TIMING: Later this evening storms could develop with the strongest occurring overnight into Thursday morning. Another round of strong to severe storms later Thursday afternoon into the evening.

THREATS: Heavy flooding rain, strong wind gusts, hail, tornadoes.

DERECHO?: I mention this only because other outlets are mentioning it. Yes, one happened this time last year, but those conditions were different from the current conditions. Also, a derecho is very rare and almost impossible to forecast. I am not forecasting one to happen here until I see one form in the OH valley. What is happening in the mid-west is what is termed a "mesoscale convective system" (MCS). Using that term in forecasts is more appropriate than saying derecho (although using the latter term brings more hype and ratings).

ADVISORIES: We are currently under a Flash Flood Watch until later tomorrow. I expect thunderstorm and tornado watches/warnings to be issued later as appropriate.

Please keep your weather radios on. I will have another update later this evening. Follow me on Twitter (@wxmanmd) for frequent storm updates.

more severe weather in Maryland

Once again, after a day of heavy rainfall and tornadoes here in Maryland, we are looking at severe weather possibility Wednesday evening into Thursday. The key word for this event is timing, especially on Thursday. Simply stated, what we have is a frontal boundary stalling near us (around the MD/PA line depending on the model you follow) and an approaching cold front on Thursday. The timing issue deals with how quickly the atmospheric conditions come together on Thursday. The sooner the clouds move in and the rain begins the less severe the storms will be since there would be no daytime heating to further destabilize the atmosphere. But the opposite is true; if the storms hold off until later Thursday, and the sun is allowed to heat the atmosphere, then there is a possibility for us to see some severe weather later Thursday. I will know more about Thursday come later Wednesday, but be aware of the potential for severe weather Thursday afternoon.

TIMING: Wednesday later in the afternoon the rain should start and the storms will follow. The system is moving in from the west. Strong thunderstorms could occur anytime after 6 and last through Thursday.

LOCATIONS (for which I forecast): Central and S MD are in the mix Wednesday and Thursday, although it appears that on Thursday S MD could take the brunt of the strongest weather (not to say other areas wont experience strong storms).

More Maryland rain & my rant

Ready for more rain? With the approach of another cold front and a disturbed weather pattern we are in for more rain the next few days. Some model estimates give us near 2 inches of rain (on top of what we received Friday).

There is some talk, in certain media outlets, of a potential derecho hitting the area Wednesday. Professionally I find this kind of speculation to be irresponsible. Derechoes are rare for our area, and their formation is such that we cannot forecast them, we can only notice patterns which may indicate their formation. I think the media outlets who are forecasting this do so for ratings and hype. Now, is a derecho possible Wednesday? There are some indications that it is possible, but not probable. It is something I will be watching, but also something I wont be able to say anything about until Wednesday. Anyone who makes claims otherwise are only guessing. Ok, off my rant and on to what I can forecast.

TIMING: Rain is likely Monday and Tuesday with thunderstorms after noon Monday through Tuesday.

UPDATE Fri morning Andrea

As I mentioned in my morning update, tropical systems over land do not do well. Andrea is losing tropical characteristics now and is being absorbed into the system to our west (as I previously mentioned). As she loses power she is drifitng more to east, probably entering MD east of the Bay Bridge Tunnel.

This means our wind and tornado risk is much lower, but our rain and flooding threats continue. We could still see 4 or more inches of rain, most of which will fall later this afternoon.

UPDATE TS Andrea in Maryland

Andrea has made landfall in FL and is moving over land just west of the Atlantic coast. She will stay over land until crossing the Chesapeake Bay. Land is not a friend to tropical systems, and Andrea is already losing some strength. Tropical systems rely on moisture to fuel them, and when over land they begin to draw in dry air, which is currently happening. When Andrea gets closer to MD she will not be any stronger than she is currently.

In all tropical systems, the NE quadrant is where we find the strongest winds, storm surge, and tornado potential. The current path of Andrea has her center crossing the Bay near the Bay Bridge Tunnel and over to OC (as I mentioned yesterday). This means that as Andrea moves up VA those in the NE quadrant will be southern tip of S MD, eastern shore and OC. Those areas have potential for tornadoes, gusty winds, and storm surge. As the center passes MD the wind will shift to the east, so those west of the Bay will have the water pushed upon their shore.

Much of MD is under a Flood Watch for Friday as many places will receive 2-4 inches of rain with some locales seeing 5-6 inches. The heaviest rainfall will be late Friday afternoon into Friday evening.

On Saturday much of Andrea's impact on MD will be over, but another Low will move in from the SW giving us chances for scattered rain and thunderstorms throughout the day Saturday.

As Friday progresses I would expect the NWS to issue flash flood products, thunderstorm watches/warnings and tornado watches/warnings. All these will be localized warnings. Keep an eye on the sky and your weather radio turned on.

I will post updates as needed Friday. Follow me on Twitter (@wxmanmd) for frequent updates.

TS Andrea & Maryland

So we have our first named tropical system. Andrea is a tropical storm, meaning wind gusts between 39 and 73 mph, although, when she reaches MD those wind speeds will be on the lower end.

Aside from Andrea, there is a cold front moving east into our area on Friday along with a trough forming to our west. The trough, a "U" shaped weather feature, will help draw Andrea northward and along the coast. Think of her as riding east of the right side of the "U". The farther east the "U" goes the less rain we in MD receive. The opposite is true. Therefore, a tricky part of this forecast is to pinpoint the location of the trough. Here are some things I know.

LOCATION: All of central, southern and the eastern shore of MD will be impacted, with the southern and eastern shore hit harder.

TIMING: Rain will start late Thursday into early Friday. This is NOT Andrea, rather it is the front from the west moving into the area. Andrea's rain and wind will begin Friday afternoon into Saturday morning (depending in the model you want to believe).

TRACKING: The center of Andrea should arrive in MD early Friday evening anywhere between the Bay Bridge and the Bay Bridge Tunnel moving NNE. But, don't just concentrate on the center since the rains and wind extend well beyond the center.

THREATS: The main impact will be heavy rain and strong wind. Locally heavy rainfall could be 3 inches or so. Those closer to the center will see more rain than those further from the center. The winds along the Atlantic coast, OC, could be in the 40's mph while further inland in the 20-30's mph. The strongest winds and rain will be on the NE and E quadrants of the center. If tornadoes form they will more likely form in the NE quadrant of the center of circulation.

I will have another update later Thursday. Follow me on Twitter (@wxmanmd) for weather tidbits and updates.

Maryland tropical system

As I mentioned earlier, there is a tropical area of interest in the Gulf near FL predicted to move up the Atlantic coast. Around Thursday into Friday this Low will be in the area of the mid-Atlantic, but so will a storm system from the West. A trough looks to form to the West of MD (trough is a "U" shaped weather feature) with the right side of the "U" just to our West. Therefore,the possibility of the tropical Low combining with another Low near MD.

There are still many areas of concern in this forecast: the speed and exact direction of the Low; the position of the trough; the intensity of the coastal Low; timing of the phasing of the two Lows. Since the coastal Low is still in FL it is too early for much specificity.

What I know thus far is that many of the models indicate the coastal Low will travel over S MD around Thursday or friday of this week. I am NOT saying we will be hit by a tropical storm. I am saying that we could experience strong wind gusts and lots of rainresulting in flash flooding.

As the systems begin to move I will have a better idea of what we will see, but for now know the end of the week will most likely be wet. I will have another update late Wednesday. Follow me daily on Twitter (@wxmanmd) for weather tidbits and updates.

Sunday storms in Maryland

The storm system that effected OK yesterday is making its way toward MD, arriving tomorrow. We wont experience the severity they did, but this is the same system. Since these past few days have been hot and humid, the atmosphere has become unstable. Tomorrow, as the cold front moves into the area it will mix with the heat and humidiy causing our storms.

TIMING: The storm activity will start in central and W MD before it does in S MD. The activity will start sometime after Noon, lasting into Monday. The model data shows three distinct lines of storms coming through the area, i.e. afternoon, evening, after midnight. The exact times will depend on the movement of the cold front and the degree of instability in the atmosphere. I'll know more tomorrow.

THREATS: The main threats are strong wind gusts and large hail. The wind gusts could be damaging, but I don't see the potential for tornadoes.

I will have another update Sunday late morning. Follow me on Twitter (@wxmanmd) for weather tidbits and updates.